Method for producing streamlined models



Aug. 21, 1945. w. H. CARAWAY ,9

METHOD FOR PRODUCING STREAMLINED MODELS Filed Jan. 8, 1943 FigJ.

W|LL|AM H CARAWAY Patented Aug. 21, 1945 UNITED STATESPATENT OFFICE METHOD FOR PRODUCING STREAMLINED MODE s William H. Caraway, Sugar Land, Tex. Application January s, 1943, Serial No. 471,740 1 Claim. (01. 73-143) (Granted under the act of March 3, 1883, as amended April 30, 1928; 370 0. G."75'7) The invention described herein may be manufactured and used by or for the Government for governmental purposes, without payment tome of any royalty thereon.

This invention relates to a method for developing streamlined forms offering the least resistance to fluid flow.

It is an object of this invention to provide a method whereby the optimal streamlined form may be determined in a minimum time and with a minimum effort.

This and other objects and advantages of my invention will become apparent upon a consideration of the following description and the accompanying drawing, in which:

Fig. 1 is a plan view of a model boat incorporating the features of the invention; and

Fig. 2 isa cross-section taken along the line 2--2 of Fig. l.

I prefer to use as a base for the model a form cut roughly to shape andprovided with means whereby it may be supported in the medium in which it is designed to operate. The rough form thus provided is then covered with a material which is soluble or erosible ,in thatparticular medium. The form is then placed under conditions analogous to the conditions for which it is designed and the medium will wear away itssurface in conformity with the pressure.

variations created by the flow. Since the erosive wooden coating II of a water soluble material is placed water passed by the model while it is held stationary or the model may be towed in the basin.

After the model has been in the basin a suflicient length of time, it is removed and can be used as a mould for producing further test models or, if

desired, the dimensions may be taken directly from it and suitably scaled for use in a full sized boat.

. Under some circumstances it may be desirable to omit the roughed-out woodenform. In this center hollowed out forming a hull which willeffect of the water is proportional to the resistance offered, the wearin away will be greatest at the areas of highest resistance and consequently the finalform taken by the model will be that which affords the least resistance to the flow of the medium. This wearing away will automatically shape the model into the optimal streamlined form.

l While my invention has particular applicability to thedesign of boats, it is clear that it is equally adaptable to other devices subjected to fluid stream flow such as aeroplane wings, fuselages,

or the like. However, for the purposes of clarity and understanding of my invention, thefollowing description will belimited to its application to boats. l d

Referring to the figures, the numeral l repre case, a block of the solidified water soluble or erosible material may be roughed out and the approximate the final form. The strengthening members 3 and 5 are placed in position and the test carried out as described above.

-Where the object to be streamlined is intended for use in a gaseous medium, the coating or hull may be made of a relatively soft material such as talc or chalk and subjected to an air blast containing fine abrasive particles such as sand,

emery, or the like.

While I have described my invention with particularity, it is to be understood that I do not Wish to be limited to the particular details and sents the hull of the roughed out model which is provided with strengthening ribs ,3 and cross strengthening members 5. to .Whichthesecuring device I may be attached. If it is desired to place the model in a basin and have it towed through the water, either the securing device 1 may be used or a line may be attached to the eye-bolt 9.

Over the outside of the hull a relatively thick arrangements disclosed since various modifications within the spirit of the invention will suggest themselves toone skilled in the art.

. Having thus described my invention, what I claim as new and wish to secure by Letters Patcut is:

A method for producing streamlined forms comprising the steps of shaping a base of rigid 3 material to approximate form, coating the base with a water soluble resin, floating the coated base in a water medium, and effecting a flow of thewater medium past said coated base under controlled conditions of displacement and relative velocities between said base and said medium, whereby areas of the coating offering highresistance are removed at a greater rate than areas offerin low resistance.

WILLIAM H. CARAWAY. 

